1. Field of the Invention
The invention relates to railroad or road vehicles for passengers, wherein intercommunication through weather- and noise-proof gangways is arranged between several successive vehicles. By extension, it also applies to the access gangways for an airplane or a ship which displays analogous kinematics.
A usual design in railroad construction, especially for railways with several indivisible vehicles or urban subways, is to provide passengers free circulation on the length of the train with the least possible amount of physical or visual obstacles. An improvement of services offered on the train, a possible distribution of the crowds and safety against aggression and vandalism are sought as much as possible by open gangway means on the entire width of the vehicles without making use of separating doors even if they are automatic.
2. Description of the prior art
Known solutions such as the various kinds of bellows that are used in the construction of traditional railway vehicles or articulated buses do not meet the requirements of total weather proofing and especially sound-proofing of the same level as that requested in the walls of the vehicles with collapsible elements.
The tramway systems use a rigid gangway, which can reach the same soundproofing level as the walls of the vehicles, each half of said gangway swivel around a vertical axis that is fitted to each vehicle body and will be fastened with appropriate sealing joints.
Patent FR No. 2 357 409 of Alsthom Atlantique describes a means to connect those two intercommunication halves with a crosswise horizontal axis close to the floor and supported by a median bogie between two vehicles, thus connected when a rolling occurs, but this system is not suitable for the linkage of more than two vehicles. The document EP No. 0134 202 from Fiat Ferroviara Savigliano describes a means for linking two intercommunication tunnel halves with a single common point ensured by a spheric swivel joint, conventional seals between the rigid walls allowing for rolling motion between the vehicles thus connected.
The document FR No. 2 569 149 from SIG describes an elastic linkage that allows for small motions between the two halves of an intercommunication tunnel, beyond which occurs a shift through friction that enables the use of conventional bellows, in conformance with the standards of the International Railroad Union (Union internationale des chemins de fer). Sealing membranes, that are U-shaped, fastened parallel to the walls of the vehicles, are described therein for the purpose of connecting a vehicle to a frame, which can swivel or flutter in relation with the vehicles.
The patent application FR No. 2 571 010 of the RATP describes an intercommunication device between railroad vehicles which is positioned, at each end of the vehicle with a flexible pneumatic joint.
Such a continuous pneumatic joint, with the necessary size, which, according to the inventor, has the shape, in a free state of a kind of large tire inner tube is impossible to manufacture with the conventional means of the rubber processing industry.
The fastening means that is described in FIG. 10 of said patent necessitates pressing the pneumatic O-ring parallel to plane and cylindrical sides. Prior to the end of manufacturing the endless joint it would be necessary to insert anchoring metal plates, the perimeter of which would have to vary during tightening for proofing.
In spite of the theoretical interest of the described device, the known means which are conventionally used in the rubber processing industry do not allow for economical manufacturing of such a large flexible pneumatic joint.
Furthermore, soundproofing measurements, described in the patent application FR No. 85 16816 of the applicant, highlights the need for a rubber thickness of about 12 millimeters in order for such a membrane to achieve acoustic efficiency. Such requirements cannot be performed by the previously described membranes because such thickness leads to insufficient flexibility in operation.
Above cited tests have shown that a double thickness of 6 millimeters would also be satisfactory, the multiplication of interfaces always favoring soundproofing.
Therefore, the analysis of the prior art indicates that a sealing joint between intercommunication means and railroad or road vehicles being simultaneously able to bear all types of pulls while in operation, with the same level of soundproofing as that of the walls of vehicles and having a good resistance to fire while being economically manufactured and easy to set up, is not known.